mirror of
https://github.com/torvalds/linux
synced 2024-09-06 18:01:05 +00:00
450 lines
14 KiB
C
450 lines
14 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _BCACHEFS_JOURNAL_H
|
|
#define _BCACHEFS_JOURNAL_H
|
|
|
|
/*
|
|
* THE JOURNAL:
|
|
*
|
|
* The primary purpose of the journal is to log updates (insertions) to the
|
|
* b-tree, to avoid having to do synchronous updates to the b-tree on disk.
|
|
*
|
|
* Without the journal, the b-tree is always internally consistent on
|
|
* disk - and in fact, in the earliest incarnations bcache didn't have a journal
|
|
* but did handle unclean shutdowns by doing all index updates synchronously
|
|
* (with coalescing).
|
|
*
|
|
* Updates to interior nodes still happen synchronously and without the journal
|
|
* (for simplicity) - this may change eventually but updates to interior nodes
|
|
* are rare enough it's not a huge priority.
|
|
*
|
|
* This means the journal is relatively separate from the b-tree; it consists of
|
|
* just a list of keys and journal replay consists of just redoing those
|
|
* insertions in same order that they appear in the journal.
|
|
*
|
|
* PERSISTENCE:
|
|
*
|
|
* For synchronous updates (where we're waiting on the index update to hit
|
|
* disk), the journal entry will be written out immediately (or as soon as
|
|
* possible, if the write for the previous journal entry was still in flight).
|
|
*
|
|
* Synchronous updates are specified by passing a closure (@flush_cl) to
|
|
* bch2_btree_insert() or bch_btree_insert_node(), which then pass that parameter
|
|
* down to the journalling code. That closure will wait on the journal write to
|
|
* complete (via closure_wait()).
|
|
*
|
|
* If the index update wasn't synchronous, the journal entry will be
|
|
* written out after 10 ms have elapsed, by default (the delay_ms field
|
|
* in struct journal).
|
|
*
|
|
* JOURNAL ENTRIES:
|
|
*
|
|
* A journal entry is variable size (struct jset), it's got a fixed length
|
|
* header and then a variable number of struct jset_entry entries.
|
|
*
|
|
* Journal entries are identified by monotonically increasing 64 bit sequence
|
|
* numbers - jset->seq; other places in the code refer to this sequence number.
|
|
*
|
|
* A jset_entry entry contains one or more bkeys (which is what gets inserted
|
|
* into the b-tree). We need a container to indicate which b-tree the key is
|
|
* for; also, the roots of the various b-trees are stored in jset_entry entries
|
|
* (one for each b-tree) - this lets us add new b-tree types without changing
|
|
* the on disk format.
|
|
*
|
|
* We also keep some things in the journal header that are logically part of the
|
|
* superblock - all the things that are frequently updated. This is for future
|
|
* bcache on raw flash support; the superblock (which will become another
|
|
* journal) can't be moved or wear leveled, so it contains just enough
|
|
* information to find the main journal, and the superblock only has to be
|
|
* rewritten when we want to move/wear level the main journal.
|
|
*
|
|
* JOURNAL LAYOUT ON DISK:
|
|
*
|
|
* The journal is written to a ringbuffer of buckets (which is kept in the
|
|
* superblock); the individual buckets are not necessarily contiguous on disk
|
|
* which means that journal entries are not allowed to span buckets, but also
|
|
* that we can resize the journal at runtime if desired (unimplemented).
|
|
*
|
|
* The journal buckets exist in the same pool as all the other buckets that are
|
|
* managed by the allocator and garbage collection - garbage collection marks
|
|
* the journal buckets as metadata buckets.
|
|
*
|
|
* OPEN/DIRTY JOURNAL ENTRIES:
|
|
*
|
|
* Open/dirty journal entries are journal entries that contain b-tree updates
|
|
* that have not yet been written out to the b-tree on disk. We have to track
|
|
* which journal entries are dirty, and we also have to avoid wrapping around
|
|
* the journal and overwriting old but still dirty journal entries with new
|
|
* journal entries.
|
|
*
|
|
* On disk, this is represented with the "last_seq" field of struct jset;
|
|
* last_seq is the first sequence number that journal replay has to replay.
|
|
*
|
|
* To avoid overwriting dirty journal entries on disk, we keep a mapping (in
|
|
* journal_device->seq) of for each journal bucket, the highest sequence number
|
|
* any journal entry it contains. Then, by comparing that against last_seq we
|
|
* can determine whether that journal bucket contains dirty journal entries or
|
|
* not.
|
|
*
|
|
* To track which journal entries are dirty, we maintain a fifo of refcounts
|
|
* (where each entry corresponds to a specific sequence number) - when a ref
|
|
* goes to 0, that journal entry is no longer dirty.
|
|
*
|
|
* Journalling of index updates is done at the same time as the b-tree itself is
|
|
* being modified (see btree_insert_key()); when we add the key to the journal
|
|
* the pending b-tree write takes a ref on the journal entry the key was added
|
|
* to. If a pending b-tree write would need to take refs on multiple dirty
|
|
* journal entries, it only keeps the ref on the oldest one (since a newer
|
|
* journal entry will still be replayed if an older entry was dirty).
|
|
*
|
|
* JOURNAL FILLING UP:
|
|
*
|
|
* There are two ways the journal could fill up; either we could run out of
|
|
* space to write to, or we could have too many open journal entries and run out
|
|
* of room in the fifo of refcounts. Since those refcounts are decremented
|
|
* without any locking we can't safely resize that fifo, so we handle it the
|
|
* same way.
|
|
*
|
|
* If the journal fills up, we start flushing dirty btree nodes until we can
|
|
* allocate space for a journal write again - preferentially flushing btree
|
|
* nodes that are pinning the oldest journal entries first.
|
|
*/
|
|
|
|
#include <linux/hash.h>
|
|
|
|
#include "journal_types.h"
|
|
|
|
struct bch_fs;
|
|
|
|
static inline void journal_wake(struct journal *j)
|
|
{
|
|
wake_up(&j->wait);
|
|
closure_wake_up(&j->async_wait);
|
|
}
|
|
|
|
static inline struct journal_buf *journal_cur_buf(struct journal *j)
|
|
{
|
|
return j->buf + j->reservations.idx;
|
|
}
|
|
|
|
/* Sequence number of oldest dirty journal entry */
|
|
|
|
static inline u64 journal_last_seq(struct journal *j)
|
|
{
|
|
return j->pin.front;
|
|
}
|
|
|
|
static inline u64 journal_cur_seq(struct journal *j)
|
|
{
|
|
return atomic64_read(&j->seq);
|
|
}
|
|
|
|
static inline u64 journal_last_unwritten_seq(struct journal *j)
|
|
{
|
|
return j->seq_ondisk + 1;
|
|
}
|
|
|
|
static inline int journal_state_count(union journal_res_state s, int idx)
|
|
{
|
|
switch (idx) {
|
|
case 0: return s.buf0_count;
|
|
case 1: return s.buf1_count;
|
|
case 2: return s.buf2_count;
|
|
case 3: return s.buf3_count;
|
|
}
|
|
BUG();
|
|
}
|
|
|
|
static inline void journal_state_inc(union journal_res_state *s)
|
|
{
|
|
s->buf0_count += s->idx == 0;
|
|
s->buf1_count += s->idx == 1;
|
|
s->buf2_count += s->idx == 2;
|
|
s->buf3_count += s->idx == 3;
|
|
}
|
|
|
|
/*
|
|
* Amount of space that will be taken up by some keys in the journal (i.e.
|
|
* including the jset header)
|
|
*/
|
|
static inline unsigned jset_u64s(unsigned u64s)
|
|
{
|
|
return u64s + sizeof(struct jset_entry) / sizeof(u64);
|
|
}
|
|
|
|
static inline int journal_entry_overhead(struct journal *j)
|
|
{
|
|
return sizeof(struct jset) / sizeof(u64) + j->entry_u64s_reserved;
|
|
}
|
|
|
|
static inline struct jset_entry *
|
|
bch2_journal_add_entry_noreservation(struct journal_buf *buf, size_t u64s)
|
|
{
|
|
struct jset *jset = buf->data;
|
|
struct jset_entry *entry = vstruct_idx(jset, le32_to_cpu(jset->u64s));
|
|
|
|
memset(entry, 0, sizeof(*entry));
|
|
entry->u64s = cpu_to_le16(u64s);
|
|
|
|
le32_add_cpu(&jset->u64s, jset_u64s(u64s));
|
|
|
|
return entry;
|
|
}
|
|
|
|
static inline struct jset_entry *
|
|
journal_res_entry(struct journal *j, struct journal_res *res)
|
|
{
|
|
return vstruct_idx(j->buf[res->idx].data, res->offset);
|
|
}
|
|
|
|
static inline unsigned journal_entry_init(struct jset_entry *entry, unsigned type,
|
|
enum btree_id id, unsigned level,
|
|
unsigned u64s)
|
|
{
|
|
entry->u64s = cpu_to_le16(u64s);
|
|
entry->btree_id = id;
|
|
entry->level = level;
|
|
entry->type = type;
|
|
entry->pad[0] = 0;
|
|
entry->pad[1] = 0;
|
|
entry->pad[2] = 0;
|
|
return jset_u64s(u64s);
|
|
}
|
|
|
|
static inline unsigned journal_entry_set(struct jset_entry *entry, unsigned type,
|
|
enum btree_id id, unsigned level,
|
|
const void *data, unsigned u64s)
|
|
{
|
|
unsigned ret = journal_entry_init(entry, type, id, level, u64s);
|
|
|
|
memcpy_u64s_small(entry->_data, data, u64s);
|
|
return ret;
|
|
}
|
|
|
|
static inline struct jset_entry *
|
|
bch2_journal_add_entry(struct journal *j, struct journal_res *res,
|
|
unsigned type, enum btree_id id,
|
|
unsigned level, unsigned u64s)
|
|
{
|
|
struct jset_entry *entry = journal_res_entry(j, res);
|
|
unsigned actual = journal_entry_init(entry, type, id, level, u64s);
|
|
|
|
EBUG_ON(!res->ref);
|
|
EBUG_ON(actual > res->u64s);
|
|
|
|
res->offset += actual;
|
|
res->u64s -= actual;
|
|
return entry;
|
|
}
|
|
|
|
static inline bool journal_entry_empty(struct jset *j)
|
|
{
|
|
if (j->seq != j->last_seq)
|
|
return false;
|
|
|
|
vstruct_for_each(j, i)
|
|
if (i->type == BCH_JSET_ENTRY_btree_keys && i->u64s)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Drop reference on a buffer index and return true if the count has hit zero.
|
|
*/
|
|
static inline union journal_res_state journal_state_buf_put(struct journal *j, unsigned idx)
|
|
{
|
|
union journal_res_state s;
|
|
|
|
s.v = atomic64_sub_return(((union journal_res_state) {
|
|
.buf0_count = idx == 0,
|
|
.buf1_count = idx == 1,
|
|
.buf2_count = idx == 2,
|
|
.buf3_count = idx == 3,
|
|
}).v, &j->reservations.counter);
|
|
return s;
|
|
}
|
|
|
|
bool bch2_journal_entry_close(struct journal *);
|
|
void bch2_journal_do_writes(struct journal *);
|
|
void bch2_journal_buf_put_final(struct journal *, u64);
|
|
|
|
static inline void __bch2_journal_buf_put(struct journal *j, unsigned idx, u64 seq)
|
|
{
|
|
union journal_res_state s;
|
|
|
|
s = journal_state_buf_put(j, idx);
|
|
if (!journal_state_count(s, idx))
|
|
bch2_journal_buf_put_final(j, seq);
|
|
}
|
|
|
|
static inline void bch2_journal_buf_put(struct journal *j, unsigned idx, u64 seq)
|
|
{
|
|
union journal_res_state s;
|
|
|
|
s = journal_state_buf_put(j, idx);
|
|
if (!journal_state_count(s, idx)) {
|
|
spin_lock(&j->lock);
|
|
bch2_journal_buf_put_final(j, seq);
|
|
spin_unlock(&j->lock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This function releases the journal write structure so other threads can
|
|
* then proceed to add their keys as well.
|
|
*/
|
|
static inline void bch2_journal_res_put(struct journal *j,
|
|
struct journal_res *res)
|
|
{
|
|
if (!res->ref)
|
|
return;
|
|
|
|
lock_release(&j->res_map, _THIS_IP_);
|
|
|
|
while (res->u64s)
|
|
bch2_journal_add_entry(j, res,
|
|
BCH_JSET_ENTRY_btree_keys,
|
|
0, 0, 0);
|
|
|
|
bch2_journal_buf_put(j, res->idx, res->seq);
|
|
|
|
res->ref = 0;
|
|
}
|
|
|
|
int bch2_journal_res_get_slowpath(struct journal *, struct journal_res *,
|
|
unsigned);
|
|
|
|
/* First bits for BCH_WATERMARK: */
|
|
enum journal_res_flags {
|
|
__JOURNAL_RES_GET_NONBLOCK = BCH_WATERMARK_BITS,
|
|
__JOURNAL_RES_GET_CHECK,
|
|
};
|
|
|
|
#define JOURNAL_RES_GET_NONBLOCK (1 << __JOURNAL_RES_GET_NONBLOCK)
|
|
#define JOURNAL_RES_GET_CHECK (1 << __JOURNAL_RES_GET_CHECK)
|
|
|
|
static inline int journal_res_get_fast(struct journal *j,
|
|
struct journal_res *res,
|
|
unsigned flags)
|
|
{
|
|
union journal_res_state old, new;
|
|
u64 v = atomic64_read(&j->reservations.counter);
|
|
|
|
do {
|
|
old.v = new.v = v;
|
|
|
|
/*
|
|
* Check if there is still room in the current journal
|
|
* entry:
|
|
*/
|
|
if (new.cur_entry_offset + res->u64s > j->cur_entry_u64s)
|
|
return 0;
|
|
|
|
EBUG_ON(!journal_state_count(new, new.idx));
|
|
|
|
if ((flags & BCH_WATERMARK_MASK) < j->watermark)
|
|
return 0;
|
|
|
|
new.cur_entry_offset += res->u64s;
|
|
journal_state_inc(&new);
|
|
|
|
/*
|
|
* If the refcount would overflow, we have to wait:
|
|
* XXX - tracepoint this:
|
|
*/
|
|
if (!journal_state_count(new, new.idx))
|
|
return 0;
|
|
|
|
if (flags & JOURNAL_RES_GET_CHECK)
|
|
return 1;
|
|
} while ((v = atomic64_cmpxchg(&j->reservations.counter,
|
|
old.v, new.v)) != old.v);
|
|
|
|
res->ref = true;
|
|
res->idx = old.idx;
|
|
res->offset = old.cur_entry_offset;
|
|
res->seq = le64_to_cpu(j->buf[old.idx].data->seq);
|
|
return 1;
|
|
}
|
|
|
|
static inline int bch2_journal_res_get(struct journal *j, struct journal_res *res,
|
|
unsigned u64s, unsigned flags)
|
|
{
|
|
int ret;
|
|
|
|
EBUG_ON(res->ref);
|
|
EBUG_ON(!test_bit(JOURNAL_running, &j->flags));
|
|
|
|
res->u64s = u64s;
|
|
|
|
if (journal_res_get_fast(j, res, flags))
|
|
goto out;
|
|
|
|
ret = bch2_journal_res_get_slowpath(j, res, flags);
|
|
if (ret)
|
|
return ret;
|
|
out:
|
|
if (!(flags & JOURNAL_RES_GET_CHECK)) {
|
|
lock_acquire_shared(&j->res_map, 0,
|
|
(flags & JOURNAL_RES_GET_NONBLOCK) != 0,
|
|
NULL, _THIS_IP_);
|
|
EBUG_ON(!res->ref);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* journal_entry_res: */
|
|
|
|
void bch2_journal_entry_res_resize(struct journal *,
|
|
struct journal_entry_res *,
|
|
unsigned);
|
|
|
|
int bch2_journal_flush_seq_async(struct journal *, u64, struct closure *);
|
|
void bch2_journal_flush_async(struct journal *, struct closure *);
|
|
|
|
int bch2_journal_flush_seq(struct journal *, u64);
|
|
int bch2_journal_flush(struct journal *);
|
|
bool bch2_journal_noflush_seq(struct journal *, u64);
|
|
int bch2_journal_meta(struct journal *);
|
|
|
|
void bch2_journal_halt(struct journal *);
|
|
|
|
static inline int bch2_journal_error(struct journal *j)
|
|
{
|
|
return j->reservations.cur_entry_offset == JOURNAL_ENTRY_ERROR_VAL
|
|
? -EIO : 0;
|
|
}
|
|
|
|
struct bch_dev;
|
|
|
|
static inline void bch2_journal_set_replay_done(struct journal *j)
|
|
{
|
|
BUG_ON(!test_bit(JOURNAL_running, &j->flags));
|
|
set_bit(JOURNAL_replay_done, &j->flags);
|
|
}
|
|
|
|
void bch2_journal_unblock(struct journal *);
|
|
void bch2_journal_block(struct journal *);
|
|
struct journal_buf *bch2_next_write_buffer_flush_journal_buf(struct journal *j, u64 max_seq);
|
|
|
|
void __bch2_journal_debug_to_text(struct printbuf *, struct journal *);
|
|
void bch2_journal_debug_to_text(struct printbuf *, struct journal *);
|
|
void bch2_journal_pins_to_text(struct printbuf *, struct journal *);
|
|
bool bch2_journal_seq_pins_to_text(struct printbuf *, struct journal *, u64 *);
|
|
|
|
int bch2_set_nr_journal_buckets(struct bch_fs *, struct bch_dev *,
|
|
unsigned nr);
|
|
int bch2_dev_journal_alloc(struct bch_dev *);
|
|
int bch2_fs_journal_alloc(struct bch_fs *);
|
|
|
|
void bch2_dev_journal_stop(struct journal *, struct bch_dev *);
|
|
|
|
void bch2_fs_journal_stop(struct journal *);
|
|
int bch2_fs_journal_start(struct journal *, u64);
|
|
|
|
void bch2_dev_journal_exit(struct bch_dev *);
|
|
int bch2_dev_journal_init(struct bch_dev *, struct bch_sb *);
|
|
void bch2_fs_journal_exit(struct journal *);
|
|
int bch2_fs_journal_init(struct journal *);
|
|
|
|
#endif /* _BCACHEFS_JOURNAL_H */
|